Research Doctorate - Doctor of Philosophy (PhD) / Masonry walls will almost invariably be required to resist lateral out-of-plane loads due to the action of wind or earthquakes; less commonly walls may be subjected to water or earth pressure or blast loading. Of particular interest is the common case which arises when the walls are supported on two or more adjacent edges. Under these conditions the masonry is subjected to a complex state of biaxial (two-way) out-of-plane bending combined with vertical in-plane compression due to the self weight of the wall and any superimposed loads. Different approaches currently exist for the design of masonry wall panels subjected to out-of-plane loads. However, these approaches are all empirical and often yield widely varying design recommendations and there has been significant criticism by proponents of the different methods regarding the use of alternative approaches. In this study an extensive program of laboratory testing in parallel with numerical analysis was conducted to examine the bending, biaxial bending in particular, behaviour of masonry walls. The aim was to provide a better understanding of the behaviour at the fundamental level towards ultimately developing a fully rational biaxial-bending failure model that can predict behaviour under any simultaneous combination of bending moments in the two principal directions, along with a superimposed compression force on the bed joints. Experimentally, 'single joint' four brick unit specimens were studied comprehensively, using a newly commissioned test rig, by subjecting them to various vertical and horizontal bending moments both separately and in combinations, along with a superimposed compression force on the bed joints. These tests provided important information about the flexural behaviour of mortar joints and the torsional behaviour of bed joints. In addition, a complete set of characterization tests was also performed to study the fundamental material properties of masonry, which were important input parameters in the numerical modelling. Numerically, a 3D non-linear finite element micro-model with cohesive contact was proposed and implemented in the ABAQUS/Standard software package. Numerical viii analyses were performed to provide rational explanations to the bending behaviours observed in the four brick unit specimen tests and evaluate a newly proposed torsion shear test method. A simplified 3D non-linear finite element micro-model was also proposed to simulate the bending behaviour of small walls. Its effectiveness was clearly demonstrated in its application to masonry walls, with or without openings, subjected to both in-plane and out-of-plane loads.

In this work, a micro-model of the catalyst layer of polymer electrolyte membrane fuel cell (PEMFC) was developed. The micro-model includes the transport phenomena and the reaction kinetics within a three dimensional micro-structure representing a sample of PEMFC catalyst layer. Proper physical boundary conditions have been described on the surfaces of the sample as well as on the interfaces between the regions through which all constituents are solved in a coupled manner. A four-phase micro-structure of CL was reconstructed, the platinum particles were resolved in the computational grid generation and the governing equations were solved within platinum region. A body-fitted computational mesh was generated for the reconstructed micro-structure of CL. The number of computational cells were optimized based on how close to an analytical sphere the magnitude of the surface area of a sphere can be captured after generating the computational cells. The interfaces with important physical phenomena were more refined than the rest of the interfaces, specially the electrochemically active reaction surface. The computational mesh was checked for a grid independent numerical solution. The Knudsen effects was included by calculating the characteristic length in the pore region. Four different cases of including Knudsen effects were studied. Also, a comparison was made between solution with and without Knudsen effects. A physical model of oxygen dissolution was developed, the oxygen dissolution at the interface between pore and ionomer was treated as an superficial phenomenon. The performance curves were produced and provided for the reconstructed micro-structure along with the distribution of field variables. A length study of the reconstructed micro-structure was conducted such that the results from the micro-modeling can capture the trend in variable distributions observed in the macro-modeling of CL or experiments. A platinum loading study was preformed and the anomalous phenomena of dramatic increase in oxygen transport resistance observed in some experimental works was explained by isolating the ionomer region of the CL micro-structure and numerically calculating the shape factor for diffusive transport. It was found that the increase in oxygen transport resistance is due to the increase in diffusion pathway and decrease in the transport surface area. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-03-06 15:55:21.564

The understanding of the deformation mechanics within porous structures is an important field of study as these materials exist in nature as well as can be manufactured industrially influencing our lives daily. The motivation of the research contained within this manuscript was inspired by the desire to understand the mechanics of an elastomeric closed–cell porous material. This type of porous material is often used in load–bearing applications such as sport helmet liners and packing material which can be subjected to large deformations at high rates. Additionally, short term transient effects were explored. In order to investigate the deformation mechanics of a closed cell elastomeric foam, a polychloroprene (neoprene) material was chosen as it was available in both rubber form and a foam with relatively consistent cell size. Compression tests were conducted on the polychloroprene rubber at strain rates ranging from 0.001/s to 2700/s which identified that it had a hyper–viscoelastic behaviour with a significant strain rate dependence. A newly developed constitutive model was created to capture the response of the polychloroprene rubber. A coupled finite element model of the polychloroprene foam was created and compared to experimental tests for validation. The model slightly over predicted the stress level response of the experimental tests. The model was used to identify momentum dissipation mechanisms that contributed to the low wave speed measurement of approximately 70 m/s determined from the model. The investigation of wave transit times through use of the model was key to interpreting experimental data. Of the morphological factors investigated, it was determined that wall thickness had the most significant impact on the stress response of the foam. The pore–scale model was useful for visualizing wavepropagation effects and deformation mechanics which was not feasible experimentally.

The understanding of the deformation mechanics within porous structures is an important field of study as these materials exist in nature as well as can be manufactured industrially influencing our lives daily. The motivation of the research contained within this manuscript was inspired by the desire to understand the mechanics of an elastomeric closed–cell porous material. This type of porous material is often used in load–bearing applications such as sport helmet liners and packing material which can be subjected to large deformations at high rates. Additionally, short term transient effects were explored. In order to investigate the deformation mechanics of a closed cell elastomeric foam, a polychloroprene (neoprene) material was chosen as it was available in both rubber form and a foam with relatively consistent cell size. Compression tests were conducted on the polychloroprene rubber at strain rates ranging from 0.001/s to 2700/s which identified that it had a hyper–viscoelastic behaviour with a significant strain rate dependence. A newly developed constitutive model was created to capture the response of the polychloroprene rubber. A coupled finite element model of the polychloroprene foam was created and compared to experimental tests for validation. The model slightly over predicted the stress level response of the experimental tests. The model was used to identify momentum dissipation mechanisms that contributed to the low wave speed measurement of approximately 70 m/s determined from the model. The investigation of wave transit times through use of the model was key to interpreting experimental data. Of the morphological factors investigated, it was determined that wall thickness had the most significant impact on the stress response of the foam. The pore–scale model was useful for visualizing wavepropagation effects and deformation mechanics which was not feasible experimentally.

<div>Single phase immiscible fluid flow in porous media is often described by Darcy’s law. However, in two-phase or multi-phase conditions, the properties of porous medium rely on the saturation of each phase. One of the constitutive equations, the relationship between capillary pressure and saturation, exhibits hysteresis property. To accurately describe two-phase immiscible fluid in porous media, some researchers used interfacial area per volume (IAV) as an additional variable. Previous experiments were done by other experimenters to support the uniqueness of IAV in capillary pressure – saturation hysteresis relationship by externally changing the capillary pressure. </div><div>A technique called Electro-Wetting On Dielectric (EWOD) was developed for sealed micro-models to examine the saturation-pressure relationship by internally manipulating the saturation which in turns affects IAV. Single-plate EWOD samples were used to select material properties and experimental parameters. These experiments found that Poly-Di-Methyl-Siloxane (PDMS) is a good dielectric material that enabled changes in the contact angle between a droplet and PDMS from ~120° (non-wetting) to ~50° (wetting). Double-plate EWOD was used to demonstrate that discrete electrodes (with PDMS as dieletric on both plates) enabled the transportation and merging of droplet(s).</div><div>A novel method was developed to incorporate EWOD into a wedge-shaped PDMS micro-model. Imbibition and drainage scans of the capillary pressure – saturation relationship (Pc-S) were performed in the channel with and without voltage. The drainage curves differed significantly between the two conditions, while the imbibition curves were similar with and without voltage. The total energy for Pc-S decreased by 70 nJ with the application of EWOD with most of difference arising from a 20 Pa decrease in pressure for the same saturation condition during drainage.</div><div>Studies were also performed to examine the amount of energy associated with depiing of fluid interfaces. A 5-step wedge-shaped micro-model with EWOD was fabricated to increase the probability of pinning during an experiment. The amount of energy released as a fluid depinned was observed to be a function of capillary pressure. More energy was released at the 1st step for higher the pressures than lower pressures. The energy released from depinning at the first step in the channel ranged from 30 – 100 nJ for pressures from 70 to 100 Pa. The occurrence and magnitude of additional depinnings along the step-shaped channel also depended on the pressure. Each successive depining released less energy.</div><div>Finally, experiments were performed to examine the range of EWOD in a sealed micro-model with discrete electrodes. When voltage was not applied directly on the fluid-fluid interface but on the solution, the voltage could still actuate the interface causing it to move and advance farther into a channel. The ability of the application of EWOD to drive fluid-fluid interfaces decreases with active electrode distance from the interface.</div>

In this thesis we provide a construction of a micro-level reserving model for an economic disability insurance portfolio. The model is based on the mathematical framework developed by Norberg (1993). The data considered is provided by Trygg-Hansa. The micro model tracks the development of each individual claim throughout its lifetime. The model setup is straightforward and in line with the insurance contract for economic disability, with levels of disability categorized by 50%, 75% and 100%. Model parameters are estimated with the reported claim development data, up to the valuation time Τ. Using the estimated model parameters the development of RBNS and IBNR claims are simulated. The results of the simulations are presented on several levels and compared with Mack Chain-Ladder estimates. The distributions of end states and times to settlement from the simulations follow patterns that are representative of the reported data. The estimated ultimate of the micro model is considerably lower than the Mack Chain-ladder estimate. The difference can partly be explained by lower claim occurrence intensity for recent accident years, which is a consequence of the decreasing number of reported claims in data. Furthermore, the standard error of the micro model is lower than the standard error produced by Mack Chain-Ladder. However, no conclusion regarding accuracy of the two reserving models can be drawn. Finally, it is concluded that the opportunities of micro modelling are promising however complemented by some concerns regarding data and parameter estimations. / I detta examensarbete ges ett förslag på uppbyggnaden av en mikro-modell för reservsättning. Modellen är baserad på det matematiska ramverket utvecklat av Norberg (1993). Data som används är tillhandahållen av Trygg-Hansa och berör försäkringar kopplade till ekonomisk invaliditet. Mikro-modellen följer utvecklingen av varje enskild skada, från skadetillfälle till stängning. Modellen har en enkel struktur som följer försäkringsvillkoren för den aktuella portföljen, med tillstånd för invaliditetsgrader om 50%, 75% respektive 100%. Modellparametrarna är estimerade utifrån den historiska utvecklingen på skador, fram till och med utvärderingstillfället Τ. Med hjälp av de estimerade parametrarna simuleras den framtida utvecklingen av RBNS- och IBNR-skador. Resultat av simuleringarna presenteras på era nivåer och jämförs med Mack Chain-Ladder estimatet. Den simulerade fördelningen av sluttillstånd och tid mellan rapportering och stängning, följer mönster som stöds av rapporterade data. Den estimerade slutkostnaden från mikro-modellen är betydlig lägre än motsvarande från Mack Chain-Ladder. Skillnaden kan delvis förklaras av en låg skadeintensitet för de senaste skadeåren, vilket är en konsekvens av färre rapporterade skador i data. Vidare så är standardfelet lägre för simuleringarna från mikro-modellen jämfört med standardfelet för Mack Chain-Ladder. Däremot kan inga slutsatser angående reservsättningsmetodernas precision dras. Slutligen, framförs möjligheterna för mikro-modellering som intressanta, kompletterat med några svårigheter gällande datautbud och parameterestimering.

Dans cette thèse, nous adressons trois projets avec l’application de microfluidique Avec le Vélocimétrie de Réflexion Totale Interne, nous avons réalisés le nanoPTV des fluides à 800 nm près de parois du solide. Nous arrivons à une précision sans précédent, par la détermination précise de la position du parois, et par la simulation de Langevin, en tenant compte des nombreux sources de biais physique, comme le mouvement Brownien, effet du cisaillement, la répulsion électrostatique entres les particules et le parois, et la défocalisation de la lentille. Nous obtenons ±5 nm and ± 10 nm de précision sur la longueur de glissement pour la solution de sucrose et de l’eau. La condition de non-glissement sur la surface hydrophile est confirmée, et un glissement sur la surface hydrophobe est observé. Nous collaborons avec A. Leshansky pour étudier la formation des gouttes sur une intersection entre un canal confiné et un réservoir profond. Cette phénomène est appelé le «step emulsificaiton». La dynamique de la formation des gouttes est étudiée expérimentalement de façon approfondie. La théorie est basée sur la dynamique des fluides dans un canal Hele-Shaw, avec les effets de forces capillaires. Nous arrivons à expliquer le mécanique du fluides derrière la formation des gouttes, inclus les taille des gouttes. Nous collaborons avec un groupe des entreprises pétrolières (AEC), pour étudier le mouvement des nano particules dans un micro model de milieux poreux. Ces particules sont supposé de faire transition une fois en contact avec l’huile ou expériencer un changement de la température. L’injection des particules dans les réservoirs de l’huile et de gaz permet de collecter l’information sur la distribution et la quantité de l’huile et de gaz. Avant l’application en mass dans l’industrie, c’est favorable de les tester dans un micro model, qui possèdes une structures similaire aux pores des roches. Nous avons testé les nano particules synthétisés par les autres membres de l’AEC, et confirmé que l’idée du micro model est une méthode efficace de prédire la performance des particules sous sol. / In this work, we have addressed three projects with the application of Microfluidics: With the technology of Total Internal Reflection Velocimetry, we realised the nano-PTV of fluid flow within 800 nm close to solid surface. We achieved unprecedented accuracy of measurement compared with the state of art, by determining precisely the wall position, and by Langevin simulation, which takes into account of the sources of biases, such as Brownian motion, shear stress, electrostatic repulsion between particles and the wall, effect of out of focus, etc. We achieved ±5 nm and ± 10 nm accuracy on the slip length determination for sucrose solution and for water. The no-slip condition on hydrophilic surface is confirmed, and a positive slip length on hydrophobic surface is clearly illustrated. This result demonstrated that the nano-PTV by TIRF is a quantitative methodology for the study of fluid flow near solid surface. We collaborated with A. Leshansky to study quantitatively the mechanism of step emulsification. The dispersed fluid and continuous fluid are co-flowing in a confined Hele-Shaw channel, before going into an unconfined pool. Drops are formed at the intersection between shallow channel and the pool. Two phases - step emulsification and large drops - are distinguished based on a well defined capillary number. We found good agreement between experiments and theory, on the step emulsification droplet size, dispersed fluid pinching dynamics, and on the shape of free interface between dispersed fluid and continuous fluid prior to pinching. We collaborated with a group of petroleum companies (AEC), to develop a technology which has potential application to the Enhanced Oil Recovery. Nano particles synthesized by the AEC is supposed to perform phase transition or deliver signals once in touch with oil. The principal idea consists in sending these nano particles into the porous media underground along with the injection fluids, and recollect them on the production well side. According to the information they deliver, the distribution of oil may be mapped. We constructed a micro model based on microfluidic technology, which mimics the complex structure of porous media of rocks. The AEC synthesized nano particles are injected into the micro model, their motion and retention can be observed in real time. This work provides important information on the particle motion in porous media, which cannot be realised in conventional core experiments.

Dans cette thèse, nous adressons trois projets avec l'application de microfluidique Avec le Vélocimétrie de Réflexion Totale Interne, nous avons réalisés le nanoPTV des fluides à 800 nm près de parois du solide. Nous arrivons à une précision sans précédent, par la détermination précise de la position du parois, et par la simulation de Langevin, en tenant compte des nombreux sources de biais physique, comme le mouvement Brownien, effet du cisaillement, la répulsion électrostatique entres les particules et le parois, et la défocalisation de la lentille. Nous obtenons ±5 nm and ± 10 nm de précision sur la longueur de glissement pour la solution de sucrose et de l'eau. La condition de non-glissement sur la surface hydrophile est confirmée, et un glissement sur la surface hydrophobe est observé. Nous collaborons avec A. Leshansky pour étudier la formation des gouttes sur une intersection entre un canal confiné et un réservoir profond. Cette phénomène est appelé le "step emulsificaiton". La dynamique de la formation des gouttes est étudiée expérimentalement de façon approfondie. La théorie est basée sur la dynamique des fluides dans un canal Hele-Shaw, avec les effets de forces capillaires. Nous arrivons à expliquer le mécanique du fluides derrière la formation des gouttes, inclus les taille des gouttes. Nous collaborons avec un groupe des entreprises pétrolières (AEC), pour étudier le mouvement des nano particules dans un micro model de milieux poreux. Ces particules sont supposé de faire transition une fois en contact avec l'huile ou expériencer un changement de la température. L'injection des particules dans les réservoirs de l'huile et de gaz permet de collecter l'information sur la distribution et la quantité de l'huile et de gaz. Avant l'application en mass dans l'industrie, c'est favorable de les tester dans un micro model, qui possèdes une structures similaire aux pores des roches. Nous avons testé les nano particules synthétisés par les autres membres de l'AEC, et confirmé que l'idée du micro model est une méthode efficace de prédire la performance des particules sous sol.

Three methods for claims reserving are compared on two data sets. The first two methods are the commonly used chain ladder method that uses aggregated payments and the relatively new method, double chain ladder, that apart from the payments data also uses the number of reported claims. The third method is more advanced, data on micro-level is needed such as the reporting delay and the number of payment periods for every single claim. The two data sets that are used consist of claims with typically shorter and longer settlement time, respectively. The questions considered are if you can gain anything from using a method that is more advanced than the chain ladder method and if the gain differs from the two data sets. The methods are compared by simulating the reserves distributions as well as comparing the point estimates of the reserve with the real out-of-sample reserve. The results show that there is no gain in using the micro-level method considered. The double chain lad- der method on the other hand performs better than the chain ladder method. The difference between the two data sets is that the reserve in the data set with longer settlement times is harder to estimate, but no difference can be seen when it comes to method choice. / Tre reservsättningsmetoder jämförs på två dataset. De första två metoderna är den välkända chain ladder-metoden som använder sig av aggregerade utbetalningar samt den relativt nya metoden double chain ladder som förutom utbetalningarna använder sig av antalet anmälda skador. Den tredje metoden baseras på mikro-nivå och kräver information om varje enskild skada, såsom anmälningstid och antalet utbetalningsperioder. De två dataseten som används är ett som innehåller skador med typiskt kortare avvecklingstider och ett som innehåller skador med typiskt längre avvecklingstider. Frågorna som behandlas är om man vinner något på att använda en mer avancerad metod än chain ladder och om det skiljer sig åt mellan dataseten. Metoderna jämförs genom simulering av reserven, men också genom att jämföra punktskattningar med den verkliga reserven. Resultaten visar att man I detta fall inte vinner något på att använda mikro-metoden. Double chain ladder å andra sidan presterar bättre än chain ladder. Skillnaden mellan de två dataseten är att det är svårare att estimera reserven när avvecklingstiden är längre, men ingen skillnad ses när det gäller val av metod